During our annual early spring visit to our farm in the SW VA Blue Ridge mountains, one of my main goals is to enjoy the sights and sounds of breeding amphibians. Since we usually go in mid-March the wood frogs, which are uncommon, have mainly finished breeding, but the peepers are in full cry, and the American toads will start breeding if the weather is warm enough. There is nothing so special as lying in bed at night and listening to the sounds of frogs engaged in raucous antics. If you go out with a light and observe, their activities are even more amazing in their primal nature. From the recently frozen earth there emerges a throng of lusty males that troup to the chosen ponds to call in order to attract the females (see photo of male with enlarged vocal sac). I was fortunate to observe the very first night of this behavior for American toads on March 18. At first there were only males and there were many staccato rejection calls by males mounted by other males. However by the next morning, a few females had found the ponds and some were already in amplexus, whereby the male grasps the female with his forelimbs (see photo). Not surprisingly, male frogs have enlarged forelimbs for this purpose.
We had to leave for Florida before the females had laid, but I have some photos of the eggs and subsequent black tadpoles from a previous year (see photos). The eggs are laid in very distinctive strings, unlike any other local amphibian. The tadpoles are very dark and stay together in groups along the edges of the ponds. This has two purposes; first it keeps them warmer and thus they grow faster. Second the tadpoles are toxic, and their association in a swarm with their siblings enhances the likelihood that any that are eaten will provide a lesson to future predators to avoid this species and in particular this group of genetically related siblings.
The American toad resembles those found all over North America but can be identified in the east by its distinctive trilling call, and the pattern of a small number of warts (usually one) per spot on the back (see photo). The large parotid poison gland on the head behind the eye is also visible and is a source of protection for toads molested by some predators. The toxin is especially effective on mucous membranes of the mouth of mammalian predators, but not against the hog-nosed snake that specializes in eating toads. Humans have found an unusual and bizarre use for the toxins from the similar Colorado River toad, which when smoked provide a hallucinogenic response. Herpetologists have decried the fact that many toads are killed for this purpose, yet the toads could be “milked ” of their gland secretion without killing them. Anyone want to set up a farm for milking toads?
Construction of several small ponds in our front yard has now provided breeding habitat for more than 50 toads and the metamorphosed toadlets emerge in thousands later in the summer. This illustrates in a small but profound way how simple techniques of wetland restoration and creation can benefit amphibians in a remarkable fashion. Build it and they will come!
Bill Dunson, Englewood, FL & Galax, VA